Replace Derived Variable with Query

refactorgram

  get discountedTotal() {return this._discountedTotal;}
  set discount(aNumber) {
    const old = this._discount;
    this._discount = aNumber;
    this._discountedTotal += old - aNumber; 
  }

image/svg+xml

  get discountedTotal() {return this._baseTotal - this._discount;}
  set discount(aNumber) {this._discount = aNumber;}